The central projections of the lateral line nerves of adult and larval Xenopus laevis and larval Rana pipiens are being studied by experimental axonal and terminal degeneration methods. Emphasis is given to the central spatial relationships between lateral line and statoacoustic nerves in larval stages and the changes that occur in these relationships during metamorphosis. Frozen sections of the brain stems will be stained by the Fink-Heimer technic to delineate terminal fields following selective transection of lateral line and statoacoustic nerves medial to their ganglia. The cellular and dendritic organization of the acousticolateralis area of the medulla will be studied by the Golgi method. Golgi preparations will be correlated with Fink-Heimer sections in order to determine whether or not lateral line and eighth nerve fibers converge onto common neurons in larval and adult toads and frog tadpoles. This type of approach can be expected to provide information on whether common cells or groups of cells transform directly into the acoustic nuclei as lateral line connections are lost, in the frog, during metamorphosis.